An interesting discussion/poll. As Playskull notes, this was in a thread in Greg's forum, started by Scott Broberg, I think. Here's the first post in that thread:
Here is the last post containing the list dated 12/22/08:
As of today, March 30th ~ 2013, I have officially "Sealed the Deal" on one of my 1-16 runs and got to categorize it as an "A"! (Geez, it only took 39 years to do! LOL!) I received my Grime Heavy in this morning's mail and immediately put it in my collection. My two remaining "B" collections each need a Grime Heavy and Scoot n/c to upgrade them to "A"s, but I'm psyched to have one of my three sets "graduate"!